• Journal of the Korean earth science society
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• v.28 no.7
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• pp.825-837
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• 2007

The researchers compiled two sets of digital terrain data released by NORI (National Oceanographic Research Institute, Korea) and NIMA (National Imagery and Mapping Agency, USA) respectively and analyzed a new set of $3"{\times}3"$ gridded terrain data in order to calculate terrain correction value in gravity in and around the Korean Peninsula. Using this new set of terrain data, the researchers developed an effective algorithm to calculate precise terrain correction value in gravity considering Earth's curvature and coded a fortran program to evaluate terrain correction value covering the surface of which the radius reaches up to 166.735 km. The researchers also calculated terrain correction value over the southern part of Korea. According to the statistics of terrain correction value calculated in and around the Korean Peninsula up to 166.735 km of surface radius, the maximum value soars to 56.508 mGal and the mean value is 4.539 mGal.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.3
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• pp.275-281
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• 2011

To acquire an underwater topographic information is necessary for the design and construction of structures in marine and inland water. It consists of water depth information by bathymetric survey and underwater bottom topography image information can be obtained by side scan sonar in different ways. For the purpose of providing high quality data by means of engineering site survey, it is necessary to apply simultaneous acquisition of two information and carry out the integrated interpretation to each other. The present research aims to obtain information of the underwater topography and water depth at the same time using interferometer technique, and to validate interferometer technique with accuracy estimation.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.14 no.2
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• pp.151-157
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• 1996

This study, experimentally, aims at presenting the methodology to construct an efficient digital terrain by com-paring and analyzing the accuracy among the existing Digital Terrain Models, develope 3-D fractal terrain model-ling program by applying digital algorithm of fractal geometry and using turbo pascal, and lastly perform basic research on constructing GSIS-based 3-D fractal terrain modelling system by integrating a PC-based GSIS Pack-age and the 3-D fractal terrain modelling program developed by this paper. The results are as follows -First, the method to produce TIN(Triangulated Irregular Network) by the combination of point data and line data was showed as an alternative to construct efficient Digital Terrain Model. Second, developing GSIS-based 3-D fractal terrain modelling system, applying fractal geometry is the basic research in developing the new terrain modelling method. also, this study presented the possibility of 3-D terrain modelling with the use of fractal.

• Journal of Navigation and Port Research
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• v.33 no.6
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• pp.451-456
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• 2009

In this paper, we presents an algorithm which generates its high-resolution DTM using a low-resolution DTM of the sea floor terrain and fractal theory. The fractal dimension of each patch region divided from the DTM is extracted and then with this information and original data, each cell region in the patch is interpolated using the midpoint displacement method and a median filter is incorporated to generate natural and smooth sea floor surface. The effectiveness of the proposed algorithm is tested on a fractal terrain map.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.12 no.2
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• pp.181-186
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• 1994

This paper applicate the digital elevation model(DEM) method in geographic information systems(GIS) on the earthwork volumes, intending to present an efficient geographic information-obtain method and an optimum earthwork volumes method after analyzing the obtain method of geographic informations which are made up of as spatial data(X, Y) and attribute data(Z), analyzing area determination method by geographic information-obtain method each other and the accuracy of earthwork volumes computation. The results of this paper showed that the method of earthwork volumes computation, which was based on the earthwork volumes-calculation grid applied by the DEM method of based grid to randomly get the geographic information of geographic transformation point and translated geography into nonlinear and unequal interval, was very efficient.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.6 no.1
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• pp.25-34
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• 1988

Digital Terrain Model is composed of two basic elements, namely, sampling and interpolation. They represent the procurement of data and the geometric reconstruction of terrain relief respectively. For evaluation DTM data, following two paremeters appear to be the most important factor, that is, the accuracy and efficiency and, in particular, the break point information significantly affect to the accuracy of DTM data. The main objective of this study is to improve the accuracy and efficiency of DTM by applying Progressive Sampling with distinct morphologic information. In this study, the total of 240 individual numerical tests has been implemented and the appropriate computer program is also developed for the test. The result of investigation shows that the Progressive Sampling with break point information improves the accuracy of DTM by 30 percent approximately.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.1
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• pp.1-7
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• 2008

The government is spending a large amount of budget to establish NGIS due to the importance of geospatial information. This paper deals with the study of schema mapping technique which can efficiently establish military topographic DB forest layer using digital forest map and other existing geospatial DB. In order to accomplish this each schema of these types of DB was analyzed then, mapping table which connects related attributes was created and finally, military topographical DB forest layer of the area of interest was efficiently established. This research was able to display solutions that resolved compatibility issues between existing geospatial DB of these types, established by the schema mapping techniques described in this research.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.11 no.4
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• pp.145-151
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• 2006

The water line moving on the intertidal flat during a flood indicates depth contours between low and high water lines. The water lines extracted from the consecutive images are rectified to get the ground coordinates of each depth contour and integrated to provide three dimensional information of Intertidal flat topography. The tidal flat outside Saemankeum-1 sea dike shows the most obvious changes of tidal flat topography after the construction of sea dikes. This tidal flat topography was observed using digital camera images, and the calculated depths were very similar to in-situ measurement data. Topography changes obtained from two different period data were also examined.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.1
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• pp.13-26
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• 2023

Recently, as the development of underground spaces has become active due to rapid urbanization and population density, interest in the ground behavior according to the construction of underground spaces is increasing. In large cities with high population density and many buildings, ground subsidence has a great impact on structures and there may be a risk of collapse, so the analysis of ground behavior due to underground construction is essential. Previous studies have been conducted on the subsidence pattern of the surface and the deformation of the tunnel when constructing the tunnel, but analysis has rarely been conducted by using actual topographic information. Therefore, this study analyzed the difference in ground behavior between the actual topography and the flat topography. As a result, it was confirmed that ground settlement occurs at higher elevations, such as in mountainous topography, and when the numerical analysis is performed considering topographical information, the crown settlement of the tunnel is up to about approx. It showed a difference of 10 mm, and it was found that the sensitivity was less in the case of displacement of tunnel wall compared to the crown settlement and ground settlement. The numerical analysis considering the actual GIS-based topographic information presented in this study can be used to obtain more accurate surface subsidence data to understand the behavior of the upper structure due to tunnel excavation.

• Bulletin of the Korean Space Science Society
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• 1996.05a
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• pp.18-18
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• 1996